Efficient management of a facility for manufacturing products such as semiconductor chips and the like requires the monitoring of all aspects of the manufacturing process. For example, it is typically necessary to track the amount of raw materials on hand, the status of work-in-process and the status and availability of machines and tools at every step in the process. Moreover, with regard to machines and tools used in the manufacturing process, it will often be necessary to schedule routine preventative maintenance (PM) procedures, as well as other diagnostic and reconditioning procedures that must be performed on a regular basis, such that the performance of the procedures does not impede the manufacturing process itself.
It is well known that PM procedures must be performed on a regular basis for several reasons. Clearly, PM assists in maintaining high production levels by helping to keep machines and tools in good working order. Moreover, keeping machines and tools in good condition assists in product quality control by ensuring that products will be manufactured to specification. In addition, with regard to semiconductor fabrication facilities, maintenance of International Standards Organization (ISO) certification requires that a manufacturer perform such procedures and then be able to substantiate such performance. For these reasons and others, it is imperative accurately to schedule and perform PM and other procedures.
One approach to achieving the foregoing objectives has been to implement in a manufacturing facility a "Management Execution System," or "MES," such as the WORKSTREAM factory management system developed by and available from Consilium, Inc. of Mountain View, Calif. WORKSTREAM enables s user to view and manipulate, to a limited extent, the status of machines and tools, or "entities," in a manufacturing environment. In addition, WORKSTREAM enables the tracking of products through the manufacturing process to enable resources to be managed in the most efficient manner. Specifically, in response to WORKSTREAM prompts, a user inputs requested information regarding work-in-process and entity status. For example, when a user performs PM on a particular entity, the operator logs the performance of the PM (an "event") into a WORKSTREAM database to update the information stored in the database with respect to the status of that entity. Alternatively, if an entity is to be put down for repair or maintenance, the operator will log this information into the WORKSTREAM database, which then prevents use of the entity until it is subsequently logged back up.
Although WORKSTREAM and similar MESs are sufficient for certain narrow purposes, such as determining the current status of a particular entity, such systems suffer several deficiencies, the most obvious of which is their lack of effective scheduling and reporting capabilities. For example, while WORKSTREAM enables a user to update the database with new information regarding the status of a particular entity, it does not allow the operator easily to generate and view a report of all scheduled maintenance for that entity over a particular time period. Moreover, WORKSTREAM is incapable of warning the operator of upcoming scheduled maintenance procedures and of notifying the operator when such procedures are overdue. Accordingly, in an unmodified WORKSTREAM environment, a user is not easily able to prearrange an appropriate day and time to perform scheduled maintenance procedures that coincides with production schedules.
Another deficiency of WORKSTREAM is that events must be logged within a predefined window of time around the scheduled due date to be appropriately accounted for. For example, assuming a procedure, such as PM, is due to be performed on an entity every thirty days, WORKSTREAM might permit the event to be logged during a three-day window beginning the day before and ending the day after the thirtieth day. If the event is logged outside of that window, either earlier or later, subsequent scheduling will be disrupted. In particular, the item will be scheduled twice, once thirty days from the original due date and once thirty days from the date the event was logged. A related deficiency is that, although there is a procedure by which a user can obtain advance scheduling information, the procedure is complicated and by no means user-friendly, making it unlikely to be used on a regular basis. Moreover, while WORKSTREAM includes a utility that can be used automatically to disable an entity if a scheduled event, such as PM, is not appropriately logged when due, this utility is deficient in that, when enabled, it is enabled for and affects other entities of the facility, thereby preventing use of entities which should not be disabled. The deficiencies suffered by this utility are magnified when an event is logged outside of the preselected window, as described above.
Therefore, what is needed is a utility for use in a manufacturing environment for tracking, monitoring and scheduling events in a manner such that a user is automatically notified of upcoming due dates and is able easily to generate and view a report of scheduled items for various entities in the facility.